I thought half of a high pressure valve, a spring that sturdy would take a lot of force to extend it, but heat would also expand it and a coil would be able to scale up the expansion due to its length. The only thing that bothers me is the spoon like depression at the right hand end. I have seen levers in the past with similar depressions at one end but they were always longer. There isn't enough space at the r h end for any significant movement. At times like this I wish my dad was still here, he was an engineer and probably would have tried to make one just to see how the parts fitted together.